Secure delivery of multimedia content, e.g., audio and video, over a network, such as an IP (Internet Protocol) network, has become an important goal for all involved with such content, e.g., content authors, content providers, and content receivers (e.g., clients). Existing approaches attempt to achieve secure delivery of multimedia content in a number of ways. Some examples are described below.
In an approach referred to as download-based security, encrypted content is downloaded to a client device in its entirety. In an alternative approach referred to as transmission-based security, content is encrypted at the time of transmission. Encrypting the content directly before transmission and decrypting directly upon receipt allows the content to be streamed, i.e., the client device can process portions of the content and is not required to receive the content in its entirety before playback.
In another approach referred to as end-to-end security, meta-information required to effectively stream content is extracted before encryption. In this approach, the content creator, or publisher, can encrypt the content before transmission to delivery systems. The content remains in this encrypted form until it reaches the client. The client retrieves rights information and decryption keys from a rights management system. Thus, while the content is not adaptable, the delivery system can stream the content to the client and end-to-end security can be maintained.